// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// A toy server, which listens on a specified address for QUIC traffic and
// handles incoming responses.
//
// Note that this server is intended to verify correctness of the client and is
// in no way expected to be performant.

#ifndef NET_TOOLS_QUIC_QUIC_SERVER_H_
#define NET_TOOLS_QUIC_QUIC_SERVER_H_

#include <stddef.h>

#include <memory>

#include "base/macros.h"
#include "net/base/ip_endpoint.h"
#include "net/quic/crypto/quic_crypto_server_config.h"
#include "net/quic/quic_chromium_connection_helper.h"
#include "net/quic/quic_config.h"
#include "net/quic/quic_framer.h"
#include "net/tools/epoll_server/epoll_server.h"
#include "net/tools/quic/quic_default_packet_writer.h"

namespace net {

namespace test {
    class QuicServerPeer;
} // namespace test

class QuicDispatcher;
class QuicPacketReader;

class QuicServer : public EpollCallbackInterface {
public:
    explicit QuicServer(ProofSource* proof_source);
    QuicServer(ProofSource* proof_source,
        const QuicConfig& config,
        const QuicCryptoServerConfig::ConfigOptions& server_config_options,
        const QuicVersionVector& supported_versions);

    ~QuicServer() override;

    // Start listening on the specified address.
    bool CreateUDPSocketAndListen(const IPEndPoint& address);

    // Wait up to 50ms, and handle any events which occur.
    void WaitForEvents();

    // Server deletion is imminent.  Start cleaning up the epoll server.
    void Shutdown();

    // From EpollCallbackInterface
    void OnRegistration(EpollServer* eps, int fd, int event_mask) override { }
    void OnModification(int fd, int event_mask) override { }
    void OnEvent(int fd, EpollEvent* event) override;
    void OnUnregistration(int fd, bool replaced) override { }

    void OnShutdown(EpollServer* eps, int fd) override { }

    void SetStrikeRegisterNoStartupPeriod()
    {
        crypto_config_.set_strike_register_no_startup_period();
    }

    void SetChloMultiplier(size_t multiplier)
    {
        crypto_config_.set_chlo_multiplier(multiplier);
    }

    bool overflow_supported() { return overflow_supported_; }

    QuicPacketCount packets_dropped() { return packets_dropped_; }

    int port() { return port_; }

protected:
    virtual QuicDefaultPacketWriter* CreateWriter(int fd);

    virtual QuicDispatcher* CreateQuicDispatcher();

    const QuicConfig& config() const { return config_; }
    const QuicCryptoServerConfig& crypto_config() const { return crypto_config_; }
    const QuicVersionVector& supported_versions() const
    {
        return supported_versions_;
    }
    EpollServer* epoll_server() { return &epoll_server_; }

    QuicDispatcher* dispatcher() { return dispatcher_.get(); }

private:
    friend class net::test::QuicServerPeer;

    // Initialize the internal state of the server.
    void Initialize();

    // Accepts data from the framer and demuxes clients to sessions.
    std::unique_ptr<QuicDispatcher> dispatcher_;
    // Frames incoming packets and hands them to the dispatcher.
    EpollServer epoll_server_;

    // The port the server is listening on.
    int port_;

    // Listening connection.  Also used for outbound client communication.
    int fd_;

    // If overflow_supported_ is true this will be the number of packets dropped
    // during the lifetime of the server.  This may overflow if enough packets
    // are dropped.
    QuicPacketCount packets_dropped_;

    // True if the kernel supports SO_RXQ_OVFL, the number of packets dropped
    // because the socket would otherwise overflow.
    bool overflow_supported_;

    // config_ contains non-crypto parameters that are negotiated in the crypto
    // handshake.
    QuicConfig config_;
    // crypto_config_ contains crypto parameters for the handshake.
    QuicCryptoServerConfig crypto_config_;
    // crypto_config_options_ contains crypto parameters for the handshake.
    QuicCryptoServerConfig::ConfigOptions crypto_config_options_;

    // This vector contains QUIC versions which we currently support.
    // This should be ordered such that the highest supported version is the first
    // element, with subsequent elements in descending order (versions can be
    // skipped as necessary).
    QuicVersionVector supported_versions_;

    // Point to a QuicPacketReader object on the heap. The reader allocates more
    // space than allowed on the stack.
    std::unique_ptr<QuicPacketReader> packet_reader_;

    DISALLOW_COPY_AND_ASSIGN(QuicServer);
};

} // namespace net

#endif // NET_TOOLS_QUIC_QUIC_SERVER_H_
